Satellites come to the rescue when ground systems fail

Satellites deliver the fallback system for emergency responders in areas where disasters have destroyed or damaged terrestrial infrastructure.

In the past, satellite communications principally facilitated voice traffic, but that is rapidly changing. “We are definitely doing more data than voice,” said Jack Deasy, civil programs director at satcom provider Inmarsat. “Data is what is driving the industry.”

The first large-scale demonstration of that shift was during the response to the Haiti earthquake in January, which left much of the island nation’s communications infrastructure in ruins.

For the first two weeks, many response teams relied almost exclusively on mobile satellite terminals for communications using Inmarsat’s Broadband Global Area Network (BGAN) service. The terminals have a throughput of 200 to 400 kilobits/sec, which was adequate for voice and more than adequate for e-mail, text messages, tweets and other data services that rescuers relied on to share information and tap expertise across the world.

The shift to data is a reflection of the increasingly mobile, connected lives people live, Deasy said. “As the world moves toward wireless connectivity, people want that capability everywhere,” especially in disaster areas.

That includes government users. “The government is often the early adopters, and they are big users, especially for mobility,” he said. About 40 percent of Inmarsat’s revenue is from government customers, and the United States is its largest customer.

The satellite industry has a 10- to 15-year lead time for fielding new systems, and Inmarsat bet in the 1990s, when it began designing the fourth-generation satellites that support BGAN, that IP data connections would become increasingly important.

The BGAN satellites launched in 2005 and 2006, and the service became fully operational in 2008. Operating in the L Band spectrum, at 1.5 GHz, it enables voice and data communications through a laptop-sized terminal that a user can set up in minutes to establish a shared 500 kilobits/sec IP channel. Voice codecs use about 4 kilobits/sec, so there also is plenty of room for data in a channel.

BGAN uses three satellites in geosynchronous orbit over the equator, each about the size of a double-decker bus with solar panels about 100 yards across. Inmarsat is preparing to deliver more bandwidth for mobile IP in its fifth generation of satellites and services. It is spending $1.2 billion for an Earth station and a new fleet of satellites that Boeing is building.

The new satellites will operate in the Ka Band, from 26.5 GHz to 40 GHz, and are supposed to be able to support throughput of 50 megabits/sec to a small terminal. The satellites are expected to launch in 2013 and 2014.